22 THE FLOATING-MATTEE OF THE AIR. 



Thousands of cases could probably be cited in which 

 the disease has shown itself in this mysterious way, but 

 where a strict examination has revealed its true parent- 

 age and extraction. Is it, then, philosophical to take 

 refuge in the fortuitous concourse of atoms as a cause 

 of specific disease, merely because in special cases the 

 parentage may be indistinct ? Those best acquainted 

 with atomic nature, and who are most ready to admit, 

 as regards even higher things than this, the potentiali- 

 ties of matter, will be the last to accept these rash 

 hypotheses. 



The Germ Theory applied to Surgery. 



Not only medical but still more especially surgical 

 science is now seeking light and guidance from this 

 germ theory. Upon it the antiseptic system of Pro- 

 fessor Lister of Edinburgh is founded. As already 

 stated, the germ theory of putrefaction was started by 

 Schwann ; but the illustrations of this theory adduced 

 by Professor Lister are of such public moment as not 

 only to justify, but to render imperative, their intro- 

 duction here. 



Schwann's observations (says Professor Lister) did not 

 receive the attention which they appeared to me to have 

 deserved. The fermentation of sugar was generally allowed 

 to be occasioned by the torula cerevisice; but it was not 

 admitted that putrefaction was due to an analogous agency. 

 And yet the two cases present a veiy striking parallel. In 

 each a stable chemical compound, sugar in tlie one case, 

 albumen in the other, undergoes extraordinary chemical 

 changes under the influence of an excessively minute quantity 

 of a substance which, regai^ded chemically, we should suppose 

 inert. As an example of this in the case of putrefaction, 

 let us take a circumstance often witnessed in the treatment 



